Printed circuit board manufacturing system

ABSTRACT

A printed circuit board manufacturing system that uses a substrate that includes a pad and an insulation layer covering the pad. The system includes an image sensor part acquiring an image of the substrate, a control part generating a control signal to form a via hole, and a laser applying part applying a laser, considering the control signal, to the part of the insulation layer that corresponds to the location information of the pad.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. divisional application filed under 37 USC1.53(b) claiming priority benefit of U.S. Ser. No. 12/010,195 filed Jan.22, 2008, which claims earlier priority benefit to Korean PatentApplication No. 10-2007-0074788 filed with the Korean IntellectualProperty Office on Jul. 25, 2007, the disclosures of which areincorporated herein by reference.

BACKGROUND

1. Field

The present invention relates to a printed circuit board manufacturingsystem and a manufacturing method thereof.

2. Description of the Related Art

Miniaturization of electronic device is accomplished by miniaturizationof electronic parts. Miniaturization of electronic parts does not meanminimized function. Electronic parts must have same functions in limitedsize. For this, researches for larger integrity have been accomplished.

For larger integrity, structure of printed circuit board is improvedfrom single-layered to multi-layered. Multi-layered printed circuitboard may be manufactured by forming a circuit pattern substrate andthen forming another circuit pattern substrate on it. Multi-layeredprinted circuit board may require interconnections between circuits oneach substrate layers.

This interconnection may be provided by pads and vias. Connectionsbetween pads and vias will be described referring to FIGS. 1 a and 1 b.FIGS. 1 a and 1 b are a front view and an enlarged cross-sectional viewof printed circuit board according to prior art. In FIGS. 1 a and 1 bare illustrated an insulation plate 100, a fiducial mark 110, a pad 120and a via 130.

Align distance between the pad 120 and the via 130 is notes as d. Thisalign distance d is defined as distance between center of pad 120 andcenter of via 130. For large d, electronic connection between the pad120 and the via 130 may not be guaranteed.

Guaranteeing the electronic connection between the pad 120 and the via130 may require large-sized pad. This may be an obstruction forintegration of circuitry on substrate, by limiting flexibility ofsubstrate design.

FIGS. 2 a and 2 b are a front view of a substrate that undergoes shapecompensation according to prior art. In FIGS. 2 a and 2 b areillustrated an insulation plate 200, 202, a fiducial mark 210, 212, apad 220, 222.

Referring to FIG. 2 (a), the shape of the insulation plate 200 in designdata is shown. Referring to FIG. 2 (b), the shape of the insulationplate 202 in manufactured result is overlapped on the shape of theinsulation plate 200.

In this case, using the information of pad 220 in design data may notguarantee the electronic connection between via and pad.

There were some researches on linear scale compensation by measuringlocation of fiducial marks 210, 212 for improved via-pad conformity.Meanwhile, linear scale compensation on the information about limitednumbers of fiducial marks can not deal with the complicated non-lineardeformation of substrates that occurs during the manufacturing process.

SUMMARY

An aspect of the invention is to provide a printed circuit boardmanufacturing system and a manufacturing method thereof, providingimproved process conformity by generating a control signal for via holeforming on a measured pad location information.

One aspect of the invention provides a method of manufacturing printedcircuit board, comprising: providing a substrate that comprises a padand an insulation layer covering the pad; acquiring an image of thesubstrate; acquiring location information of the pad by analyzing theimage of the substrate; forming a via hole by removing a part of theinsulation layer that corresponds the location information of the pad;and forming a via by filling the via hole with a conductive material.

Acquiring location information of the pad may comprises extracting acenter coordinate of area that corresponds to the pad in the image ofthe substrate.

Forming the via hole comprises laser drilling process. Forming the viaby laser drilling process may comprises generating a control signal forvia hole forming based on the location information of the pad andapplying laser to the part of the insulation layer that corresponds tothe location information of the pad, considering the control signal.

Another aspect of the invention provides a printed circuit boardmanufacturing system, using a substrate that comprises a pad and aninsulation layer covering the pad, comprising; an image sensor part foracquiring an image of the substrate, a control part for generating acontrol signal for via hole forming and a laser applying part forapplying laser, considering the control signal, to the part of theinsulation layer that corresponds to the location information of thepad.

Additional aspects and advantages of the present invention will be setforth in part in the description which follows, and in part will beobvious from the description, or may be learned by practice of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 a and 1 b are a front view and an enlarged cross-sectional viewof printed circuit board according to prior art.

FIGS. 2 a and 2 b are a front view of a substrate that undergoes shapecompensation according to prior art.

FIG. 3 is a flowchart of printed circuit board manufacturing methodaccording to a disclosed embodiment of the invention.

FIGS. 4 a, 4 b, 4 c and 4 d are a diagram of printed circuit boardmanufacturing method according to a disclosed embodiment of theinvention.

FIG. 5 is a schematic illustration of printed circuit boardmanufacturing system according to a disclosed embodiment of theinvention.

FIGS. 6 a, 6 b and 6 c are distribution illustrations of number of viaholes to distance between real via hole and ideally conformed via holeaccording to prior art and a disclosed embodiment of the invention.

DESCRIPTION OF EMBODIMENTS

Embodiments of a printed circuit board manufacturing system and amanufacturing method thereof according to certain aspects of theinvention will be described below in more detail with reference to theaccompanying drawings. In the description with reference to theaccompanying drawings, those components are rendered the same referencenumber that are the same or are in correspondence regardless of thefigure number, and redundant explanations are omitted. Also, the basicprinciples will first be described before discussing the preferredembodiments of the invention.

Reference will now be made in detail to the embodiments of the presentgeneral inventive concept, examples of which are illustrated in theaccompanying drawings, wherein like reference numerals refer to the likeelements throughout. The embodiments are described below in order toexplain the present general inventive concept by referring to thefigures.

FIG. 3 is a diagram of printed circuit board manufacturing methodaccording to a disclosed embodiment of the invention. FIG. 4 is aflowchart of printed circuit board manufacturing method according to adisclosed embodiment of the invention. In FIG. 3 and FIG. 4, areillustrated a first insulation layer 400, a pad 402, a second insulationlayer 404, a via hole 406, a via 408, an image sensor 410, a laserapplying part 420, a laser source 422 and a galvanometer 424.

Providing substrate including pad S310 will be described, referring toFIG. 4 (a). The first insulation layer 400 may be composed of polymerresin (polyimide, epoxy and the likes). The pad 402 is a part of circuitpattern formed in the first insulation layer 400. The pad 402 may beconnected electronically to other circuit patterns formed in the firstinsulation layer 400.

The circuit pattern comprising the pad 402 may be formed by subtractiveprocess and additive process. The subtractive process is patterningprocess by removing unnecessary part of conductive material applied onan insulation layer. The additive process is patterning process bynon-electrical plating method applied on an insulation layer. Thesemi-additive process is patterning process using electrical platingprocess and etching process after non-electrical plating. In addition,pre-formed circuit pattern may be buried to the first insulation layer.The pattern may be composed of metal material as Cu and may have Aucoating or Sn coating on it.

The second insulation layer 404 is covering the pad 402. The secondinsulation layer 404 may be formed by applying insulation material onthe first insulation layer 400 comprising the pad 402. The secondinsulation layer 404 may be composed of same materials that composingthe first insulation layer 400.

Meanwhile, a printed circuit board made by present embodiment may bemulti-layered and there may be another insulation layer, comprisingcircuit pattern, under the first insulation layer 400.

Acquiring image of substrate including pad S320 will be describedreferring FIG. 4 (b). the image of the substrate may be acquired by theimage sensor 410 installed in front of the substrate.

For example, the image sensor 410 may be a CCD camera. Because thatmaterials composing the first and the second insulation layer 400, 404differ from materials composing the pad 402 in optical characteristics,the first and the second insulation layer 400, 404 may be distinguishedfrom pad 402 in the image of the substrate. In addition, hightransparency of the second insulation layer 404 for wavelength used bythe image sensor 410 may provide relatively clear image.

The acquired image of the substrate may include information aboutcircuit pattern including the pad 402. Then, defining an area about thepad 402, in the image of total circuit pattern image, may be required.

location information of the pad may be acquired by extracting centercoordinate of the pad area, defined like this. For example, the centercoordinate of the pad area may be extracted by converting the pad areato black and white image and calculating center of mass in the convertedarea.

In the step S320 the location of the pas 402 may be directly measured,not conjectured by scale compensation.

Meanwhile, a substrate may comprise a fiducial mark, and locationinformation of the fiducial mark may be acquired from the image of thesubstrate. The location information of the fiducial mark may be anorigin in the location information of the pad. Also, the locationinformation of the fiducial mark may be an assistant information thatidentifies the align direction of the substrate.

Forming via hole by laser drilling S330 will be described referring FIG.4 (c). The via hole 406 is formed by applying laser to the secondinsulation layer 404, using the laser applying part 420 comprising thelaser source 422 and the galvanometer 424.

As mentioned above, information about laser applying point may beacquired by analyzing the image of the substrate from the image sensor410. This step S330 may improve conformity between the pad 402 and thevia hole 406 by forming the via hole 406, using the measured locationinformation of the pad.

A CO2 laser, a YAG laser and excimer laser may be used as a laser sourcein the present embodiment. Also, a pulse laser may be utilized for thelaser source stability.

Forming via by filling via hole with conductive material S340 will bedescribed referring FIG. 4 (d). The via 408 may be formed by filling thevia hole 406 with a conductive material.

The via 408 may be utilized to provide electrical connection to circuitson the substrate that will be formed in subsequent process and to formexternal electrode. In case that additional circuit pattern layer isformed on the substrate comprising the via 408, additional processforming a insulation layer covering the via 408 and process formingcircuit pattern on the insulation layer may be required.

Conductive material filling process may be accomplished by electricalplating, screen printing and etc. the conductive material may be metallike Cu and Au, and conductive polymer. Conductive material comprisingcorrosion-resistive element like Ni may be utilized when the via 408forms the external electrode.

FIG. 5 is a schematic illustration of printed circuit boardmanufacturing system according to a disclosed embodiment of theinvention. In FIG. 5 are illustrated a substrate 500, a pad 502, a viahole 504, an image sensor part 510, a laser applying part 520, a controlpart 530 and a support part 540.

The image sensor part 510 acquires the image of the substrate includingthe pad and transfer the image to the control part. As mentioned above,the image sensor part 510 may be configured with a CCD camera.

Meanwhile, the wavelength utilized by the image sensor part may not bein visible light band. To distinguish the circuit pattern comprising thepad 502 form the insulation layer, infrared and x-ray band light may beapplied to the substrate in image acquisition.

The control part 530 generates a control signal for via hole forming byanalyzing the image from the image sensor part 510.

The location information of the pad 502 may be acquired by analyzing theimage of the substrate. For this, the image processing mentioned above,referring to FIG. 3 and FIG. 4, may be accomplished.

The control signal for via hole forming may comprise a control signalfor galvanometer angle control and a control signal for laser powercontrol. Controlling the driving angle of the galvanometer, laser beamcould be controlled. The laser power reduction, for outside of the viahole area, may prevent unnecessary removal of the insulation layer.

The laser applying part 520 may apply the laser to the substrate 500according to the control signal for via hole forming from the controlpart 530. In this embodiment, the laser applying part 520 comprises thelaser source 522 and the galvanometer 524.

The galvanometer 524 scans the laser in x-y directions on the substrateby controlling the angle of a reflection body coupled to a drivingmotor. The laser source generates laser beam that could remove theinsulation layer of the substrate 500.

As mentioned above, the control signal for via hole forming comprises acontrol signal for angle control of the galvanometer 524 and a controlsignal for power control of the laser source 522.

Meanwhile, a laser applying part comprising a galvanometer is used inthis embodiment and the configuration of optical system may be modified.For example, an optical system that moves a reflection body and a lasersource in x-y plane may be configured.

Meanwhile, the printed circuit board manufacturing system 500 maycomprise an image acquisition stage by the image sensor 510 and a laserprocess stage by the laser applying part 520. These two stages mayhandle different substrates simultaneously.

The support part 540 supports the substrate 500 during the processes. Ifnecessary, the substrate 500 may be carried with the support partcoupled.

FIG. 6 is distribution illustrations of number of via holes to distancebetween real via hole and ideally conformed via hole according to priorart and a disclosed embodiment of the invention. In FIG. 6 areillustrated a substrate 600, an ideally conformed via hole 602 and areal via hole 604.

The ideally conformed via hole 602 is a perfectly conformed via hole toa pad on the substrate. The center location of the ideally conformed viahole 602 matches perfectly with the center location of the pad on thesubstrate. The real via hole 604 may be separated from the ideallyconformed via hole 602, by distance d2, due to the errors in process.

FIG. 6 (b) illustrates a distribution of number of the via holes todistance d2, according to prior art. FIG. 6 (c) illustrates adistribution of number of the via holes to distance d2, according to aembodiment of the present invention.

Referring to FIG. 6 (b), most via holes have separation distance largerthan 10 micrometer. Meanwhile, Referring to FIG. 6 (c), the separationdistance remains smaller than 10 micrometer. Like this, the conformitybetween a via and a pad may be improved by considering measured padlocation information for via hole forming process.

Meanwhile, FIG. 6 (c) may be understood as an example, not limiting thebenefit of the present invention.

According to certain embodiments of the invention as set forth above,the printed circuit board manufacturing system and a manufacturingmethod thereof may allow provides improved process conformity, even ifthe substrate has partial or nonlinear deformation, by considering thelocation information of the pad in the via hole forming. The improvedconformity may allow more flexibility to substrate design and moreintegrity for circuitries on printed circuit board.

While the above description has pointed out novel features of theinvention as applied to various embodiments, the skilled person willunderstand that various omissions, substitutions, and changes in theform and details of the device or process illustrated may be madewithout departing from the scope of the invention. Therefore, the scopeof the invention is defined by the appended claims rather than by theforegoing description. All variations coming within the meaning andrange of equivalency of the claims are embraced within their scope.

1. A printed circuit board manufacturing system, using a substrate thatcomprises a pad and an insulation layer covering the pad, comprising: animage sensor part to acquire an image of the substrate; a control partto generate a control signal to form a via hole; and a laser applyingpart to apply a laser, considering the control signal, to a part of theinsulation layer that corresponds to location information of the pad. 2.The printed circuit board manufacturing system of claim 1, wherein thecontrol part extracts a center coordinate of an area that corresponds tothe pad in the image of the substrate.